| Geant4 Cross Reference |
1 // 1 //
2 // ******************************************* 2 // ********************************************************************
3 // * License and Disclaimer 3 // * License and Disclaimer *
4 // * 4 // * *
5 // * The Geant4 software is copyright of th 5 // * The Geant4 software is copyright of the Copyright Holders of *
6 // * the Geant4 Collaboration. It is provided 6 // * the Geant4 Collaboration. It is provided under the terms and *
7 // * conditions of the Geant4 Software License 7 // * conditions of the Geant4 Software License, included in the file *
8 // * LICENSE and available at http://cern.ch/ 8 // * LICENSE and available at http://cern.ch/geant4/license . These *
9 // * include a list of copyright holders. 9 // * include a list of copyright holders. *
10 // * 10 // * *
11 // * Neither the authors of this software syst 11 // * Neither the authors of this software system, nor their employing *
12 // * institutes,nor the agencies providing fin 12 // * institutes,nor the agencies providing financial support for this *
13 // * work make any representation or warran 13 // * work make any representation or warranty, express or implied, *
14 // * regarding this software system or assum 14 // * regarding this software system or assume any liability for its *
15 // * use. Please see the license in the file 15 // * use. Please see the license in the file LICENSE and URL above *
16 // * for the full disclaimer and the limitatio 16 // * for the full disclaimer and the limitation of liability. *
17 // * 17 // * *
18 // * This code implementation is the result 18 // * This code implementation is the result of the scientific and *
19 // * technical work of the GEANT4 collaboratio 19 // * technical work of the GEANT4 collaboration. *
20 // * By using, copying, modifying or distri 20 // * By using, copying, modifying or distributing the software (or *
21 // * any work based on the software) you ag 21 // * any work based on the software) you agree to acknowledge its *
22 // * use in resulting scientific publicati 22 // * use in resulting scientific publications, and indicate your *
23 // * acceptance of all terms of the Geant4 Sof 23 // * acceptance of all terms of the Geant4 Software license. *
24 // ******************************************* 24 // ********************************************************************
25 // 25 //
26 // G4HelixImplicitEuler implementation 26 // G4HelixImplicitEuler implementation
27 // 27 //
28 // Helix Implicit Euler: 28 // Helix Implicit Euler:
29 // x_1 = x_0 + 1/2 * ( helix(h,t_0,x_0) 29 // x_1 = x_0 + 1/2 * ( helix(h,t_0,x_0)
30 // + helix(h,t_0+h,x_ 30 // + helix(h,t_0+h,x_0+helix(h,t0,x0) ) )
31 // Second order solver. 31 // Second order solver.
32 // Take the current derivative and add it to 32 // Take the current derivative and add it to the current position.
33 // Take the output and its derivative. Add th 33 // Take the output and its derivative. Add the mean of both derivatives
34 // to form the final output 34 // to form the final output
35 // 35 //
36 // Author: W.Wander <wwc@mit.edu>, 03/11/1998 36 // Author: W.Wander <wwc@mit.edu>, 03/11/1998
37 // ------------------------------------------- 37 // -------------------------------------------------------------------------
38 38
39 #include "G4HelixImplicitEuler.hh" 39 #include "G4HelixImplicitEuler.hh"
40 #include "G4ThreeVector.hh" 40 #include "G4ThreeVector.hh"
41 41
42 G4HelixImplicitEuler::G4HelixImplicitEuler(G4M 42 G4HelixImplicitEuler::G4HelixImplicitEuler(G4Mag_EqRhs *EqRhs)
43 : G4MagHelicalStepper(EqRhs) 43 : G4MagHelicalStepper(EqRhs)
44 { 44 {
45 } 45 }
46 46
47 G4HelixImplicitEuler::~G4HelixImplicitEuler() << 47 G4HelixImplicitEuler::~G4HelixImplicitEuler()
>> 48 {
>> 49 }
48 50
49 void 51 void
50 G4HelixImplicitEuler::DumbStepper( const G4dou 52 G4HelixImplicitEuler::DumbStepper( const G4double yIn[],
51 G4ThreeVect 53 G4ThreeVector Bfld,
52 G4double 54 G4double h,
53 G4double 55 G4double yOut[])
54 { 56 {
55 const G4int nvar = 6 ; 57 const G4int nvar = 6 ;
56 G4double yTemp[6], yTemp2[6]; 58 G4double yTemp[6], yTemp2[6];
57 G4ThreeVector Bfld_endpoint; 59 G4ThreeVector Bfld_endpoint;
58 60
59 // Step forward like in the explicit euler c 61 // Step forward like in the explicit euler case
60 // 62 //
61 AdvanceHelix( yIn, Bfld, h, yTemp); 63 AdvanceHelix( yIn, Bfld, h, yTemp);
62 64
63 // now obtain the new field value at the new 65 // now obtain the new field value at the new point
64 // 66 //
65 MagFieldEvaluate(yTemp, Bfld_endpoint); 67 MagFieldEvaluate(yTemp, Bfld_endpoint);
66 68
67 // and also advance along a helix for this f 69 // and also advance along a helix for this field value
68 // 70 //
69 AdvanceHelix( yIn, Bfld_endpoint, h, yTemp2) 71 AdvanceHelix( yIn, Bfld_endpoint, h, yTemp2);
70 72
71 // we take the average 73 // we take the average
72 // 74 //
73 for( G4int i = 0; i < nvar; ++i ) 75 for( G4int i = 0; i < nvar; ++i )
74 { 76 {
75 yOut[i] = 0.5 * ( yTemp[i] + yTemp2[i] ); 77 yOut[i] = 0.5 * ( yTemp[i] + yTemp2[i] );
76 } 78 }
77 79
78 // NormaliseTangentVector( yOut ); 80 // NormaliseTangentVector( yOut );
79 } 81 }
80 82